CN102841452B - Laser polarization schlieren pick-up unit - Google Patents
Laser polarization schlieren pick-up unit Download PDFInfo
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- CN102841452B CN102841452B CN201110360767.1A CN201110360767A CN102841452B CN 102841452 B CN102841452 B CN 102841452B CN 201110360767 A CN201110360767 A CN 201110360767A CN 102841452 B CN102841452 B CN 102841452B
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Abstract
The present invention relates to a kind of schlieren pick-up unit adopting polarized laser imaging, belong to detection technique field.This device is the schlieren imaging detection system be made up of LASER Light Source, 1/2nd wave plates, shaping lens group, Amici prism, aperture, spherical reflector, quarter-wave plate, polaroid, diaphragm, the schlieren edge of a knife, imaging lens group, image-forming component.Described schlieren detects and adopts polarization laser as imaging source, can realize coaxial laser schlieren imaging.Device can adopt the conventional mechanical schlieren edge of a knife, liquid crystal light valve also can be adopted as the schlieren edge of a knife, realize non-focusing schlieren imaging.Apparatus structure set forth in the present invention is stablized, not easily off resonance under microgravity environment and high acceleration impact, and has good Practical significance in the research of microgravity environment flame.
Description
Technical field
The present invention relates to a kind of new pattern laser schlieren pick-up unit, particularly relate to a kind of schlieren pick-up unit adopting polarized laser imaging, belong to detection technique field.
Background technology
Combustion process under microgravity condition is the emerging research field in Combustion.On the one hand, microgravity condition provides the method for best reduction Effect of Nature Convection, and the study mechanism for combustion process has important value, and this to the important industrial safety process study such as dust combustion and blast highly significant.On the other hand, under microgravity condition catch fire and fire spread has great importance for the fire safety evaluating of spacecraft, the research of microgravity fire spread by preventing for space capsule, the enforcement of fire-fighting safety engineering provides scientific basis.Microgravity combustion has become the important research direction in Combustion, and laser schlieren pick-up unit of the present invention, mainly for the particular surroundings of microgravity, high acceleration condition, has high stability, can adapt to the advantages such as heavy caliber.
Schlieren imaging is used for by L.Fuoacutl in the detection of optical glass refractive index at first.Schlieren system is according to the shape of light by measured stream place, directional light schlieren and the large class of taper light schlieren two can be divided into, the optical imaging concept of two class schlierens and the analytical approach of schlieren figure identical, difference is to be that light is converged in parallel rays or taper by measured flow field area.Directional light schlieren is divided into transmission-type and reflective two kinds, and transmission-type schlieren imaging system adopts lens as main focusing optic, and reflective schlieren imaging system adopts concave mirror as main focusing optic.The quality of optical imaging of transmission-type is good, but it is very difficult to process bigbore spherical lens; Existing reflective schlieren imaging system adopts the scheme of off-axis imaging usually, and optical system exists astigmatism and coma two class aberration, and quality of optical imaging is poor.
Liquid crystal light valve, as a kind of shaping device, can realize the accurate shaping to injecting laser beam.Liquid crystal light valve be filled with between two panels transparent electrode substrate 10 microns thick to row twisted liquid crystal, make the major axis of liquid crystal molecule that the distortion of 90 ° occur between substrate.To row twisted liquid crystal (twistednematicliquidcrystal, TNLC) when molecular material does not have a voltage-drop loading, light retrodeviates polarization state by half-twist through light valve, if have voltage-drop loading on row twisted liquid crystal, the orientation of molecule is subject to the impact of extra electric field, and can be changed along molecular orientation by polarisation of light state.This just makes impressed voltage can accurately control through polarisation of light state.This structure is placed between two orthogonal polaroids, just can realizes the modulation of laser amplitude.Liquid crystal light valve is exactly the array be made up of above-mentioned shaping infinitesimal, the length of each infinitesimal and wide all between 10 microns to 40 microns, array laterally comprises 1 to 2048 infinitesimal of closely arrangement, longitudinally also can comprise 1 to 2048 infinitesimal, light beam can be subdivided into the beamlet of infinitesimal number by such a array, realizes the accurate modulation to light beam.The shaping figure loaded by quick-replaceable, can carry out shaping, and the speed of shaping can reach musec order to energy (power) distribution directly writing laser.Liquid crystal light valve comprises transmission-type and reflective two kinds.Transmission liquid crystal light valve is to the incident beam modulation light that also scattering is unnecessary with reflection, forms required figure in transmission direction; Reflective liquid crystal light valve is to the incident beam modulation light that also scattering is unnecessary, and reflection direction is formed required figure.
In existing patent, the patent for schlieren imaging structure is a lot, such as US Patent No. 3582185, US3617130, US3631409, US20030103194, US20090060134 etc.Wherein US Patent No. 3847484 has set forth transmission-type schlieren detection system, adopts multiple lens to be gathered into the technical scheme of picture; For reflective schlieren imaging, such as US Patent No. 3582185, US3617130 have set forth respective claimed range respectively.US3582185 require that a kind of array edge of a knife segmentation light beam carries out the technical scheme detected, and US3617130 then require that reflective schlieren imaging system is carried out in a kind of catoptron two faces that adopt.
Current reflective laser schlieren imaging system all adopts the structure from axle, if adopt spherical reflector can there is very large optical path difference, aspheric surface therefore must be adopted to eliminate all kinds of aberration.But non-spherical reflector is expensive, poor stability, under gravity environment, fill school after, can off resonance be there is in the environment of non-gravity environment and high acceleration, reduce systems axiol-ogy precision.The present invention can effectively solve the problem, keeping system stability in the environment of non-gravity environment and high acceleration, and can make the large-scale schlieren imaging system that bore is greater than 1 meter, has good Practical significance.
Summary of the invention
The object of the invention is to provide a kind of novel laser schlieren pick-up unit, realizes high-quality imaging by polarization structure.The object of the present invention is achieved like this:
The laser schlieren pick-up unit that the present invention relates to as shown in Figure 1, comprising: LASER Light Source 1, first 1/2nd wave plate 2, shaping lens group 3, Amici prism 4, aperture 5, second 1/2nd wave plate 6, first spherical reflector 7, first quarter-wave plate 8, first polaroid 9, first diaphragm 10, second diaphragm 11, second polaroid 12, second quarter-wave plate 13, second spherical reflector 14, the schlieren edge of a knife 15, imaging lens group 16, image-forming component 17.
In described technical scheme, described LASER Light Source 1 be used for produce schlieren detect laser.
In described technical scheme, the polarisation of light direction that described first 1/2nd wave plate 2 LASER Light Source 1 be used for described in adjustment sends.
In described technical scheme, described shaping lens group 3 is used for the light that described LASER Light Source 1 sends to converge to a very little focus.
In described technical scheme, described Amici prism 4 is used for isolating parallel polarization laser beam from detection laser is intrafascicular.
In described technical scheme, described aperture 5 is used for carrying out spatial filtering.
In described technical scheme, second described 1/2nd wave plate 6 are used for parallel polarization laser beam to be rotated into vertical polarization laser beam.
In described technical scheme, described first spherical reflector 7 is used for reflecting and converges laser beam is directional light.
In described technical scheme, described first quarter-wave plate 8 is used for vertical polarization laser beam to be rotated into circularly polarized laser light beam, or circularly polarized laser Beam rotation is become parallel polarization laser beam.
In described technical scheme, described first polaroid 9 is used for the superincumbent vertical polarization laser beam of reflected illumination, and transmissive parallel polarized laser beam.
In described technical scheme, described first diaphragm 10 and second diaphragm 11 are used for isolating detected region.
In described technical scheme, second described polaroid 12 is used for the superincumbent vertical polarization laser beam of reflected illumination, and transmissive parallel polarized laser beam.
In described technical scheme, second described quarter-wave plate 13 is used for parallel polarization laser beam to be rotated into circularly polarized laser light beam, or circularly polarized laser Beam rotation is become vertical polarization laser beam.
In described technical scheme, second described spherical reflector 14 is used for reflecting and converges laser beam is directional light.
In described technical scheme, the described schlieren edge of a knife 15 is used for blocking the light beam passed through, and can be the conventional mechanical edge of a knife, also can be the equivalent edge of a knife that liquid crystal light valve is formed.
In described technical scheme, described imaging lens group 16 is used for detection beams converge in image device.
In described technical scheme, described image-forming component 17 is used for detecting the laser light illumination passed through.
Compared with the prior art the present invention has following advantage:
Common reflective schlieren imaging system adopts the non-spherical reflector structure optically focused from axle, the poor stability of such system, especially off resonance can occur under microgravity environment and high acceleration impact, cause measuring accuracy to reduce because quality of optical imaging declines.Apparatus structure set forth in the present invention is more stable, not easily off resonance under microgravity environment and high acceleration impact, and has good Practical significance in the research of microgravity environment flame.
Accompanying drawing explanation
Fig. 1 is a kind of structure of laser schlieren imaging system.
Fig. 2 is the structure of another kind of laser schlieren imaging system.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is described in more detail.
Embodiment 1
With reference to figure 1, make a laser polarization schlieren pick-up unit.This device selects the surface-emission laser diode of Coherent company as LASER Light Source 1.The laser that LASER Light Source 1 sends is adjusted to horizontal polarization light after first 1/2nd wave plate 2, the shaping lens group 3 then through being made up of 2 plano-convex lenss.Shaping lens group 3 by detection laser beams converge to a point.Amici prism 4 is placed in after shaping lens group 3, before shaping lens group 3 focus, is used for laser beam thoroughly to become the horizontal polarization light of High Extinction Ratio.Aperture 5 is placed in the focus of detection laser light beam, is used for carrying out spatial filtering.Second 1/2nd wave plate 6 is placed on after aperture 5, is used for detection laser Beam rotation to become orthogonal polarized light.The detection laser light beam of vertical polarization after the reflection of first polaroid 9, then through first quarter-wave plate 8, becomes circularly polarized light, and coaxial irradiation is on first spherical reflector 7.The beams converge dispersed is become directional light by first spherical reflector 7, and reflection is through first quarter-wave plate 8, and detection laser light beam is rotated into horizontal polarization laser, transmission first polaroid 9.The detection light beam of transmission is through first diaphragm 10, second diaphragm 11 comprising surveyed area, and second polaroid 12, is rotated into circularly polarized light by second quarter-wave plate 13.Then after second spherical reflector 14 reflects, then orthogonal polarized light is rotated into by second quarter-wave plate 13.Detection laser light beam, after the reflection of second polaroid 12, successively through the schlieren edge of a knife 15, imaging lens group 16, enters in image-forming component 17.Here lens combination 16 is the subsidiary imaging lens of a science CCD that chooses, the hard-edge edge of a knife of what the schlieren edge of a knife 15 was chosen is arrowhead form, is used for reducing the impact of diffraction.Image-forming component is the science CCD product of Thorlabs company.
Embodiment 2
With reference to figure 2, make a laser polarization schlieren pick-up unit.This device selects an all solid state YLF laser as LASER Light Source 1, and the light that LASER Light Source 1 sends is the linearly polarized laser of vertical direction.The detection laser light beam of vertical polarization, after the reflection of first polaroid 9, through first quarter-wave plate 8, becomes circularly polarized light, and coaxial irradiation is on spherical reflector 7.The beams converge dispersed is become directional light by spherical reflector 7, and reflection is through quarter-wave plate 8, and detection laser light beam is rotated into horizontal polarization laser, transmission first polaroid 9.The detection light beam of transmission is through first diaphragm 10, second diaphragm 11 comprising surveyed area, and second polaroid 12, is rotated into circularly polarized light by second quarter-wave plate 13.Then after second spherical reflector 14 reflects, then orthogonal polarized light is rotated into by second quarter-wave plate 13.Detection laser light beam is after the reflection of second polaroid 12, and the schlieren edge of a knife 15 successively through being made up of liquid crystal light valve enters in image-forming component 17.What the schlieren edge of a knife 15 was here chosen is the many stripeds edge of a knife adjusting in real time on liquid crystal light valve, show, schlieren occlusion detection while simultaneously can realizing multiple spot, the schlieren that also can realize salt free ligands by loading soft aperture slot detects, and liquid crystal light valve is the LCX016AL-6 type transflective liquid crystal light valve product of Sony Corporation.Image-forming component 17 is the CMOS camera product of Shaanxi Wei Shi company.
Claims (4)
1. adopt the laser schlieren pick-up unit that polarization structure realizes, comprising: LASER Light Source, first 1/2nd wave plate, shaping lens group, Amici prism, aperture, second 1/2nd wave plate, first spherical reflector, first quarter-wave plate, first polaroid, first diaphragm, second diaphragm, second polaroid, second quarter-wave plate, second spherical reflector, the schlieren edge of a knife, imaging lens group, image-forming component;
Described LASER Light Source is used for producing detection laser;
Described first 1/2nd wave plate is placed near shaping lens group, before Amici prism, is used for the polarization direction of adjusting laser beam;
Described shaping lens group is used for carrying out shaping focusing to the light that LASER Light Source sends, and makes it converge through small holes;
Described Amici prism is used for filtering detection laser, extracts horizontal polarization light;
Described aperture is used for filtering detection laser, improves beam quality;
Second described 1/2nd wave plate are placed on after aperture, are used for detection laser Beam rotation to become orthogonal polarized light;
After described first polaroid is placed on second 1/2nd wave plate, be used for coaxial by vertical polarization detection laser beam reflection on first spherical reflector, and transmission level Polarization Detection laser beam;
Described first quarter-wave plate, along after light path is placed on first polaroid, is used for vertical polarization detection laser Beam rotation to become circularly polarized light, or circularly polarized light is rotated into horizontal polarization detection laser, and transmission level Polarization Detection laser beam;
Described first spherical reflector, along after light path is placed on first quarter-wave plate, is used for reflection detection laser light beam;
Described first diaphragm and second diaphragm are that high permeability is dull and stereotyped, between region be schlieren imaging surveyed area;
After second described polaroid is placed on second diaphragm, act on identical with first polaroid, i.e. transmission level Polarization Detection laser beam, and be used for reflecting the vertical detection laser beam of described second spherical reflector reflection;
Second described quarter-wave plate is along after light path is placed on second polaroid, act on identical with first quarter-wave plate, namely horizontal polarization detection laser Beam rotation is used for become circularly polarized light, or circularly polarized light is rotated into vertical polarization detection laser, and transmissive Homeotropic Polarization Detection laser beam;
After second described spherical reflector is placed on second quarter-wave plate, act on identical with first spherical reflector, be namely used for reflecting detection laser light beam;
The described schlieren edge of a knife is placed on the reflected light path of second polaroid, is used for blocking detection light beam, realizes schlieren imaging;
After described imaging lens group is placed on the schlieren edge of a knife, be used for focal imaging on image-forming component;
After described image-forming component is placed on imaging lens group, be used for gathering image.
2. by laser schlieren pick-up unit according to claim 1, it is characterized in that, the described schlieren edge of a knife can be the conventional mechanical diaphragms edge of a knife, also can be the equivalent edge of a knife of the image construction of liquid crystal light valve and loading thereof; If the mechanical diaphragms edge of a knife of routine, can be the flat limit edge of a knife, may also be the edge of a knife of the special shapes such as arrow, or the combination of multiple pattern or the array edge of a knife.
3. by laser schlieren pick-up unit according to claim 1, it is characterized in that, the described schlieren edge of a knife can be the equivalent edge of a knife of the image construction of liquid crystal light valve and loading thereof, liquid crystal light valve can carry out real-time control by external program, load dynamic change through image, the movement of equivalent stop, substitutes the mechanical motion system of edge of a knife outside.
4. by laser schlieren pick-up unit according to claim 3, it is characterized in that, the described schlieren edge of a knife can be the equivalent edge of a knife of the image construction of liquid crystal light valve and loading thereof, liquid crystal light valve can carry out real-time control by external program, the soft aperture slot image that fringing transmissivity gradually changes, forms the salt free ligands edge of a knife; The edge of a knife array of equivalence or the time dependent edge of a knife can be loaded, realize the compensation of detection of dynamic.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110360767.1A CN102841452B (en) | 2011-11-15 | 2011-11-15 | Laser polarization schlieren pick-up unit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110360767.1A CN102841452B (en) | 2011-11-15 | 2011-11-15 | Laser polarization schlieren pick-up unit |
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| CN102841452A CN102841452A (en) | 2012-12-26 |
| CN102841452B true CN102841452B (en) | 2016-04-06 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109141835B (en) | 2018-09-28 | 2019-12-24 | 中国兵器工业标准化研究所 | Projection and schlieren two-in-one optical test system |
| CN109444077B (en) * | 2018-11-30 | 2020-04-07 | 中山大学 | Quantitative measurement system and method for refractive index field based on phase calibration |
| CN110207928A (en) * | 2019-05-15 | 2019-09-06 | 中国科学院西安光学精密机械研究所 | It is a kind of using the uniform high-resolution schlieren optical system of aspherical height |
| CN111131724B (en) * | 2019-12-31 | 2022-02-18 | 浙江大华技术股份有限公司 | Vehicle window colorful pattern eliminating system, method and device, controller and storage medium |
| CN112611518B (en) * | 2020-12-09 | 2023-01-20 | 广东电网有限责任公司电力科学研究院 | Gas leakage detection device and method for SF6 insulated metal closed type switch equipment |
| CN113639955B (en) * | 2021-10-15 | 2022-01-04 | 中国空气动力研究与发展中心计算空气动力研究所 | Device for measuring concave panel boundary layer disturbance |
| CN116678583B (en) * | 2023-01-12 | 2024-04-05 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Schlieren system based on phase modulation and adjusting method thereof |
| CN117388525B (en) * | 2023-12-12 | 2024-02-13 | 南方科技大学 | Airborne airflow speed measuring system, method, electronic equipment and storage medium |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH489812A (en) * | 1968-04-24 | 1970-04-30 | Eidophor Ag | Schlieren optical system |
| US3617130A (en) * | 1969-12-10 | 1971-11-02 | Us Air Force | Simplified schlieren system |
| DE3428272C2 (en) * | 1983-07-29 | 1986-03-27 | Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt e.V., 5000 Köln | Device for the quantitative measurement of acoustic signals in gases |
| CN101846812A (en) * | 2010-04-29 | 2010-09-29 | 中国科学技术大学 | Schlieren quasi-monochromatic light source device |
| CN201897502U (en) * | 2010-12-01 | 2011-07-13 | 中国科学院西安光学精密机械研究所 | Schlieren device for testing far-field focus faculae of high-power laser |
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